10 Java Developer Interview Questions Every Hiring Manager Should Ask

Candidate for new java developer position

What sets apart a good Java developer candidate from a great one?

Java is still amongst the most in-demand computer languages. Its robust feature-set powers everything from Android apps to Tomcat web servers. The object-orientated approach is favored by companies throughout the world to develop apps of all types and sizes.

Interviewing Java developers requires specialist knowledge of the field.

CTOs and CIOs must ask the right questions to determine if the Java interview went well. Or if the candidate merely read a Dummy’s Guide the night before.

This article offers 10 questions for your company to consider when interviewing for Java jobs.

From language-specific knowledge to teamwork, ethics, and attitude, we break down what you need to know.

Read on to find the perfect addition to your team. And ensure they’re the right person for the role.

Preparing for a Java Developer Interview

Hiring for any job takes careful planning as asking the wrong questions could lead to costly re-hiring down the road. That’s especially true of a high-level language like Java.

It’s important to realize that Java is not the same as JavaScript.

Unlike the lightweight web development language, Java is a complex platform. It takes years to master and fully grasp the fundamentals that set it apart from other codebases. That includes concepts like polymorphism, inheritance, and interfaces.

It’s considered good practice for a senior developer to conduct the interview like CTOs or a Chief Information Officer. They will understand the candidate’s responses and how they relate to the position’s requirements.

The interview should cover the following areas:

  • Java coding knowledge and skills
  • Other technology skills e.g. databases, Cloud development, etc.
  • Previous experience
  • Working as a team
  • Personal goals and achievements

The latter elements cover all potential IT staffing candidates and relate to the individual as a person.

Will they fit into your organization? Do they work well in a team? What is the evidence of this?

To help break-down the sections, we’ve created the following ten questions.

Each is designed to gauge how much the candidate understands about Java. And how that relates to real-world issues they’ll encounter in your workplace.

Questions also link to modern methods of coding and practices, like Agile development. Incorporating them into your own interviews will yield a higher rate of success.

1. Please Explain Object-Orientated Programming and Outline Its Benefits

Object-orientated programming or OOP lies at the heart of Java.

The goal is to convert real-world entities into code by treating them as objects. Each object interacts and communicates with other objects. They then work together to form a complete application.

The candidate should mention the following terms:

  • Classes
  • Abstraction
  • Inheritance
  • Polymorphism

These methodologies create a ‘code once, use everywhere’ system of development. Apps are easier to debug because there’s less code. And the right technique will reduce development time.

The candidate should explain what these terms mean. They should then outline their benefits and give real-world examples using their own experiences.

2. What Is Java Inheritance? Give Examples

Following on from OOP, this question breaks down the key concept of inheritance.

Java inheritance represents the relationship between objects. Instead of writing the same code for lots of objects, write it once. Other objects ‘inherit’ this code and overwrite its methods to fulfill their tasks.

An example is a car.

Instead of writing code for every make of car, create one Car class. It can accelerate(), brake(), and refuel(). A Ford class inherits the Car class so it can accelerate and brake etc. But its refuel() method is different so it overrides it to make it unique.

The candidate should offer a similar example to outline how inheritance and method overriding work. Preferably, this should include one of their prior projects and how inheritance solved a real-life problem.

3. How Would You Connect a Java Application To a Database?

Java developers need to be proficient in database integration and design.

Nearly all applications utilize some sort of database to store and edit content. That includes SQL-based platforms like MySQL to modern NoSQL systems like MongoDB.

The candidate should demonstrate how to connect to a local or networked database using the JDBC driver. If the job is for Android development, they should explain how to add the com.google.cloud.sql dependency to Gradle.

Give extra merit for Cloud database connectivity knowledge and experience.

Google’s Firebase platform is used by Java developers to store data objects. Application development in AWS and Microsoft Azure use a variety of database types including:

  • Relational e.g. Amazon RDS and SQL Server
  • Key-value e.g. Amazon DynamoDB
  • Graph e.g. Amazon Neptune

Although understanding database architecture isn’t essential, it’s good to know. Candidates that display a thorough knowledge of the subject are worth taking note of.

4. What Is JSON and What Is It Used For?

JavaScript Object Notation or JSON is a simple way to transfer data between applications.

It’s lightweight and string-based and most programming languages can read and edit it. JSON is also designed to easily fit into JavaScript programming which fuels much of modern web design.

The candidate should explain what JSON is and how strings get encoded and decoded in Java.

They should demonstrate knowledge of JSON packages such as org.json.simple.JSONObject. Android Java developers must detail how the JSONObject and JSONArray classes work.

Real-world examples of sending and receiving data through a web API will demonstrate competency.

Most application programming interfaces (APIs) return results in JSON. A good candidate will elaborate on APIs and the benefits they bring to your business.

5. Give an Example of a Poorly Designed Java App You’ve Seen Developed

The next set of questions relate to coding practice and architecture.

Experienced candidates will immediately recall applications that they found to be terrible. They will explain how a faulty user interface (UI) or poor code led to a bad user experience (UX). They might also share their own stories from the beginning of their programming days.

Candidates who falter on this question demonstrate that they haven’t dealt with failure.

Perhaps they’re inexperienced or have only worked in exceptional development teams. Either way, you need to know if they understand the difference between good and poor app design.

Candidates should also relay what they have learned from bad practices.

Have they changed how they work as a result? Did they speak with the original developer to share their thoughts? What was their contribution as a team member to turn the situation around?

6. Do You Use Github or Another VCS Tool?

Version Control System or VCS records changes to files that you can retrieve at a later date.

Most Java developers use a VCS to store all changes made to their source code. They can revert to working code if the current source breaks functionality. That could include reverting an entire project to just one page of code.

An online distributed VCS offers an even bigger advantage: code branching.

Other developers can mirror or clone the existing code then branch off on their own to develop it. Many popular open-source apps get developed this way. Changes get combined into the main branch and everyone benefits.

VCS is all about safeguarding code and promoting development in a team.

A candidate’s response should demonstrate these concepts. It should outline how versioning control works and why it’s important.

As Github powers the majority of VCS, the candidate should underline the platform’s importance.

Preferably, they will have experience in Github versioning control. That includes setting up repositories and checking in/out code. Command-line experience is a bonus but GUI is fine too.

7. Outline the Software Development Life Cycle

The Software Development Life Cycle or SDLC offers 6 steps to build quality applications.

  1. Planning
  2. Analysis
  3. Design
  4. Implementation
  5. Testing and Integration
  6. Maintenance

The objective of this task is to see if the candidate understands where they fit into the picture.

They should offer examples of their involvement in the SDLC. That will probably include the design, implementation, and testing phases.

If they have experience in offering technical support, they should relay their role. Additionally, they must understand and relate to each team member’s position and how the work gets completed.

Give credit if they ask how your business operates.

Someone who believes they know everything might clash within a new setting. They should bring experience to the table but be able to adapt to a new way of working.

8. What Motivated You To Become a Java Developer?

Golden Technology had a vision over twenty years ago.

We wanted technology that was people-inspired. One that would conquer new horizons. We wanted to build a family of IT professionals that would develop the world.

You can follow in our footsteps by asking your potential employee what motivated them to become a Java developer.

If you see passion flowing as they talk then take notice. Programming isn’t for everyone and some see it as a 9 to 5 job.

Those who understand that developing isn’t just about code are worth their weight in gold. Software can change the world – do they share that vision?

Candidates should also discuss other languages and expertise they possess.

Give extra credit for each coding language and experience developing with it. If they’ve worked with Cloud technologies and modern infrastructures give bonus points.

9. Give 3 Benefits of Working in an Agile Team Environment

Agile software development offers quick, robust, and secure app creation within a team environment.

Agile is an umbrella term for practices that value the 12 core Agile principles. Some of those include:

  • Welcoming constantly changing requirements
  • Short development timescales
  • Communication between developers and business personnel
  • Technical excellence through continual testing

The key to a successful Agile team is communication.

Instead of working as an isolated unit, team members constantly talk with each other. Candidates who show a reluctance to communicate must get marked down. But if they share how Agile has helped them personally then give them credit.

Agile hierarchy includes a term called Scrum.

Like a rugby team, this framework promotes learning through experience with the help of peers. It describes tools, meetings, and roles that work together to provide a stronger structure to manage work.

The candidate should demonstrate a working knowledge of Agile principles and Scrum mentality. Experience counts here, so don’t just listen for keywords like ‘sprints’ or ‘standups’.

Candidates should clearly show their role and how it benefited them and the overall project.

Where they a Scrum Master, taking charge of the team? Did they see the process as effective? If not, what were the issues?

The goal is to see how they will fit into your company’s workforce.

10. Where Do You See Yourself in Five Years?

This standard question is often seen as a final ‘trick’ by the interviewer.

Candidates get uncomfortable as answering ‘running the place’ seems too bold. Whereas ‘in a better job’ probably isn’t the best response.

As an employer, you want to hear an honest and realistic reply.

If you know the job doesn’t offer advancement then the interviewee should highlight that. They should desire to improve their worth, both to your company and to themselves. Being honest with you about future aspirations is a positive response.

The question also demonstrates a well-thought-out strategy for their personal future.

A good work/life ratio is essential to a balanced lifestyle. Candidates should speak about their pursuits outside of the office. What do they want to do with their life overall?

A Java developer interview should remain holistic. Remember, you are hiring a person, not a coding machine. 

Java Interviews and IT Staffing Cincinnati

A Java interview needs to cover a lot of bases, not just programming.

The perfect candidate should be proficient in Java and related technologies. But they should also work well in a team and offer something to your company that sets them apart.

The main question is, how do you find the right Java developer to hire in the first place?

Golden Technology has an unrivaled history of serving the hiring managers of Cincinnati based fortune 1000 companies.

We assist CIOs, CTOs, and VPs to find the most suitable candidates for the job. Whether it’s in Ohio, Kentucky, Indiana, or throughout the US, we deliver every time.

Hire talent now by contacting us and scheduling a discovery call.

Contract the best Java developers with confidence with Golden Technology. Trust your most precious resource to us – your future employees.

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